impetus

The grant for building the opera house gave impetus to the city's cultural life.

2.

(broadly) the momentum of a moving body, especially with reference to the cause of motion.

Origin of impetus

1650-1660

1650-60; < Latin: an attack, literally, a rushing into, perhaps by haplology from *impetitus (though the expected form would be *impetītus; see appetite), equivalent to impetī-, variant stem of impetere to attack (im-im-1 + petere to make for, assault) + -tus suffix of v. action